v3.26.1
REVENUES - Revenues Disaggregated by Line of Business and Geographical Area (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Revenue $ 2,185 $ 1,898 $ 4,264 $ 3,822
United States        
Disaggregation of Revenue [Line Items]        
Revenue 1,218 992 2,398 2,057
Non-U.S.        
Disaggregation of Revenue [Line Items]        
Revenue 967 906 1,866 1,765
MA        
Disaggregation of Revenue [Line Items]        
Revenue 925 888 1,851 1,747
MA | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 928 891 1,857 1,753
MA | United States        
Disaggregation of Revenue [Line Items]        
Revenue 409 381 808 756
MA | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 409 381 808 756
MA | Non-U.S.        
Disaggregation of Revenue [Line Items]        
Revenue 516 507 1,043 991
MA | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 516 507 1,043 991
MA | Decision Solutions (DS) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 423 413 855 818
MA | Decision Solutions (DS) | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 178 162 353 329
MA | Decision Solutions (DS) | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 245 251 502 489
MA | Research and Insights (R&I) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 256 249 511 485
MA | Research and Insights (R&I) | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 141 139 279 267
MA | Research and Insights (R&I) | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 115 110 232 218
MA | Data and Information (D&I) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 246 226 485 444
MA | Data and Information (D&I) | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 90 80 176 160
MA | Data and Information (D&I) | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 156 146 309 284
MIS        
Disaggregation of Revenue [Line Items]        
Revenue 1,260 1,010 2,413 2,075
MIS | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 1,312 1,060 2,516 2,174
MIS | United States        
Disaggregation of Revenue [Line Items]        
Revenue 809 611 1,590 1,301
MIS | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 809 611 1,590 1,301
MIS | Non-U.S.        
Disaggregation of Revenue [Line Items]        
Revenue 451 399 823 774
MIS | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 451 399 823 774
MIS | Corporate Finance (CFG) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 651 512 1,284 1,076
MIS | Corporate Finance (CFG) | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 433 314 905 705
MIS | Corporate Finance (CFG) | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 218 198 379 371
MIS | Structured Finance (SFG) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 151 135 288 273
MIS | Structured Finance (SFG) | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 104 91 198 191
MIS | Structured Finance (SFG) | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 47 44 90 82
MIS | Financial Institutions (FIG) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 222 191 416 382
MIS | Financial Institutions (FIG) | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 119 99 221 194
MIS | Financial Institutions (FIG) | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 103 92 195 188
MIS | Public, Project and Infrastructure Finance (PPIF) | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 224 162 400 325
MIS | Public, Project and Infrastructure Finance (PPIF) | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 152 107 264 211
MIS | Public, Project and Infrastructure Finance (PPIF) | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 72 55 136 114
MIS | Total ratings revenue        
Disaggregation of Revenue [Line Items]        
Revenue 1,248 1,000    
MIS | Total ratings revenue | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 1,248 1,000 2,388 2,056
MIS | Total ratings revenue | United States        
Disaggregation of Revenue [Line Items]        
Revenue 808 611    
MIS | Total ratings revenue | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue     1,588 1,301
MIS | Total ratings revenue | Non-U.S.        
Disaggregation of Revenue [Line Items]        
Revenue 440 389    
MIS | Total ratings revenue | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue     800 755
MIS | MIS Other        
Disaggregation of Revenue [Line Items]        
Revenue 12 10    
MIS | MIS Other | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 12 10 25 19
MIS | MIS Other | United States        
Disaggregation of Revenue [Line Items]        
Revenue 1 0    
MIS | MIS Other | United States | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue     2 0
MIS | MIS Other | Non-U.S.        
Disaggregation of Revenue [Line Items]        
Revenue $ 11 $ 10    
MIS | MIS Other | Non-U.S. | Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue     $ 23 $ 19